In Xcode 14.3.1 using SwiftUI and preview, why doesn't the preview display both of my Views? (It shows them on separate previews)

My app is made up of two Views. When I run it on the emulator, it looks like the following (minus the red bar - I added that to the image to make explaining this a bit easier):

All of the controls above the red line are in one View and the one control below the red line (OtherOne in green) are on another View.

When I run the app it looks like the one you see in that image.

However, when I do a preview I get two different View pages in XCode.

It looks like this:

I have to click each of the (ContentView) bubbles at the top so I can see each one separately.

Question

I'm wondering why the preview doesn't show them as merged -- the same way I see them in the actual app?

My Swift app looks like :

import SwiftUI

@main
struct FirstSwiftUIApp: App {
    var body: some Scene {
        WindowGroup {
            ContentView()
            OtherView()
        }
    }
}

My ContentView file has two separate Views (ContentView & OtherView) in it and looks like the following:

import SwiftUI

// preview moved to the top so you can see it contains both Views
struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
        OtherView()
    }  
}

struct ContentView: View {
    var body: some View {
        VStack {
            Image(systemName: "globe")
                .imageScale(.large)
                .foregroundColor(.accentColor)
            Text("Hello, world!")
            Button(action:
                    {print("it worked")}){Text("simple")}
            Button(action:{
                if let url = URL(string:"https://newlibre.com/librestore"){
                UIApplication.shared.open(url)
            }
                
            }){
                Text("Load NewLibre")
            }.padding(5)
        }
        .padding()
    }
}

struct OtherView: View{
    var body : some View{
        VStack{
            Button(action:
                    {print("This is the other one!")})
            {
                Text("OtherOne")
                    .font(.title2)
                    .foregroundColor(.green)
                
            }
            
        }.padding()
    }
}

You have two previews because you currently have two items at the root of your previews:

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView() // <-- 1
        OtherView()   // <-- 2
    }  
}

In order to get them to display in one preview, you should have one root (in, for example, a VStack):

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        VStack {
           ContentView()
           OtherView()
        }
    }  
}